A packet sending method includes: receiving, by a first node, a first broadcast data packet sent by a second node; and if a sequence number of the first broadcast data packet equals 1 plus a sequence number of a latest data packet saved by the first node, and the first node does not receive, within a first preset time period, a first acknowledgement indication for the first broadcast data packet of the second node, sending, by the first node, a first broadcast acknowledgement packet when the first preset time period elapses, where the first broadcast acknowledgement packet includes the first acknowledgement indication, and the first acknowledgement indication includes the sequence number of the first broadcast data packet and an address of the second node. This method could resolve acknowledgement packet implosion while ensuring broadcast packet reliability of a wireless mesh network.